I want to ask which is the cheapest solution for getting 640x512 resolution of thermal images or videos using DJI products or  may be other than DJI
there are already many option like inspeire + zenmuse xt
matrice 200,210, 210 rtk with zenmuse xt2
matrice 600 with flir lense
if somone has already doing this job please guide me. i want to use the thermal drone imaging for inpection of Natural gas Transmission instalations

You want it mounted on a drone?
Because DJI has the enterprise version of the Mavic 2 for that.

Someone recently posted a thread about software security issues among the major drone manufacturers / software developers and it contained a link to an article with a YouTube video at the end about a "bird named drone company" [HINT HINT].

However, I personally haven't used or seen it tested so it all just comes down to one's budget and the equipment's capabilities being balanced in order to compel one to purchase any option they may be considering.

DJI Forum: DJI Drones Banned By Tech Supplier

I was working in building inspection and we have a MAVIC PRO mounted with a FLIR camera. We didnt have real time data but with the bugdet we got we manage to do the job. think about it